Motor vehicle safety device



J. P. CALDWELL MOTOR VEHICLE SAFETY DEVICE Filed Nov. 25, 1938 lllllll (707L71 P UaZcZweZl 3% W W 5 July 18, 1939.

Patented July 18, 1939 UNITED STATES PATENT OFFICE; MOTOR @21 gfrnrr DEVICE I 1 11 1 12:23 2, iz r srnu it masi 4 chill!!- (CL 188-110) My invention relates to certain new and useful mechanism for applying the brakes of motor vehicles, especially the air brakes of trucks, busses, etc. The air brakes usually require but little pressure on the brake pedal to effect the application of the'brakes.

The invention has for its primary object to provide means to apply the brakes whenever the operator removes his hands from the steering wheel. In this way, should an operator faint or fall dead at the wheel, the brakes will be immediately applied and a wreck avoided. When a person dies at the wheel it is usually from heart failure .or a stroke: when death strikes in this 15 way, the body becomes limp and the operator's hands drop from the wheel.

Further, the invention has for an object to control the brake/application effecting device by the use of a photo-tube and a photo-electric relay.

Other'objects of the invention will in part be obvious and in part will be pointed out hereinafter.

To the attainment of the aforesaid objects and ends the invention still further resides in the novel details of construction, combination and arrangement of parts, all of which will be first fully described in the following detailed description, and then be particularly pointed out in the appended claims, reference being had to the accompanying drawing, in which:-

Fig. 1 is a diagrammatic plan view of the invention as applied to a bus.

Fig. 2 is a detail section and elevation of parts 'of a motor vehicle and of the invention.

Fig. 3 is a plan view of the electro-magnetically released latch device for holding the brake actuator inactive.

Fig. 4 is an-enlarged detail cross section on 40 the hue 4-4 of Fig. 3.

Referring now to the accompanying drawing, which is illustrative of the principle .of the invention, l is the instrument board or the dash board of the vehicle, 3 the usual brake pedal, I l the clutch pedal, 5 the accelerator pedal, and

6 the usual steering wheel. N In applying the invention to the vehicle, 1 provide one or more light sources 8 whose rays are directed in planes parallel and adjacent that of the steering-wheel G across, below and, preferably, also above the wheel onto a focusing mirror 8 which collects the rays of light and focuses them onto the photo-tube of the electric eye Ill.

This tube is electrically connected to a photo electric relay H by suitable wiring b, the con-. trolled circuit being indicated by ain Fig. 1.

An electro-magnet 29 of an electro-magnetically released latch device (Figs. 3 and 4) is connected in this circuit a so that when current flows 6 a will be opened.

The portion of the apparatus which is actuated by the photo-electric relay includesnot only the 15 latch device shown particularly in Figs. 3 and 4 but also a brake applicator which is best shown in Fig. 2 and comprises a vertical guide I2 suitably supported in a fixed position in any approved way, as for example by a support l3. In 20 the guide I2 is a heavy bar M of metal, angular in cross section so as not to swivel in the guide. The bar ll has a foot l5 carrying a rubber or other yieldable pad l6. At its upper end I! the bar is formed with a notch l8 to receive the latch 25 I!) (see Fig. 4) to hold the bar up, as in Fig. 2.

Attached to the bar is a piston rod 35 which works in a cylinder 33'forming a sort of air-' spring dash pot to enable a service application of the brakes to be obtained, instead of an emer- 30 gency application, if desired. In order that the speed of drop of bar Il may be regulated for the above purposes, the cylinder is provided with an adjustable air leak or bleed valve 36 of any approved construction The cylinder is prefer- 35 air beneath, more or less, the air escaping through regulating valve 36, allowing the further fall of bar M, at the desired speed, to press pedal 3 4 down to set the brakes. 1

When it is desired to render the bar I! inoperative it may be held in either the elevated position (brakes ofl) or the lowered position (brakes on) by means of a clamp screw 38.

The latch device used'may be such a one as is commonly used as the keeper in electric door unlatching systems and it comprises generally a case l in which is pivoted, at 20, the latch 19 whose heel 2| lies in the socket of'a keeper 22, pivoted 58 at 23, and having an arm 25 to lie under the armature lever 2'. The lever 28 is pivoted at 21 and has a spring 28 which always tends to keep the armature over the arm II to hold the keeper 22 from movement. The usual leai spring 24 is employed continuously to tend to move latch II to its holding position (Fig. 4). The magnetic coils 29 are wired to the terminals 80 on an insulation block held across an opening in the case 1..

A guide 8| is secured to the face of the latch device for the end ll of bar ll when the bar is raised so it cannot be jarred loose accidentally.

If desired, compressed air may be admitted to the cylinder 33 above piston 34 via pipe II and regulating valve ll from an air storage tank (not shown), or other suitable source, to increase the acceleration of bar ll during its fall toward the pedal. 7

Operation When the operator is in normal driving position, his hands on the wheel intercept some of the rays oflight travelingirom light sources 8 to the photo-tube in the electric eye ll, thereby 1 reducing the light which reaches the photo-tube and consequently the relay ll causes the circuit a to de-energize magnets 29. The bar ll', which haslbeen previously raised and latched up, will be held in the elevated position. Should the operator, however, remove both hands from wheel v6 so that the full flow of light rays may pass via focusing reflector 9 to eye ll current will be caused to flow through circuit 11, thereby energiz-' ing magnet 29 to rock armature lever 28, release keeper 22 and instantly permit weighted bar I l to rock latch I 9 counter-clockwise (down), in Fig. 4, to free b'arJl, which drops down with pad i6 onto pedal 3, the weight of the bar then causing pedal 3 to be depressed and thereby effeet a setting or the brakes through the usual pedal actuated or controlled system (not shown) of the vehicle. 7

The brakes may be voluntarily locked" set by tightening the thumb screw 38 with plunger bar it down, or the bar may be "locked out of action (up) in the same manner.

While I have shown and described one embodiment of the invention, it will be obvious that other changes in the position of the light source I and eyelfl, etc., may have to be made toadapt the arrangement to particular types of vehicles, but such modification-and others which will be clear to those skilled in the artmay be made without departing from the spirit of the invention and the appended claims.

What I claim is: a

1. In motor vehicles having brake systems in which the brakes are applied by movement of a brake pedal, and having a steering wheel, the combination with the brake pedal of means to apply braking pressure to the pedal, electrically releasable means to hold said applying means inoperative, and means including a photo-electric relay and photo-tube, and an electric circuit including said relay and said electrically releasable means, and light ray projecting means in cooperative relation tothe steering wheel and to said photo-tube and constructed so that only when the steering wheel'is clear will it eilect a release of said electrically releasable means to effect the operation oi 'said brake pressure applying means.

2. In motor vehicles having brake systems in photo-tube, in circuit with said electro-magnetic means to eifect'energizationof the same under predetermined light influence on the photo-tube or said relay, and means to direct light rays over and adjacent said steering wheel onto said phototube, the arrangement being such that when the rays are interrupted by hands on the steering wheel the electro-magnetic means will be inoperative.

3. In motor vehicles having brake systems in which the brakes are applied by movement 01' a brake pedal, and having a steering wheel, the

combination with the steering wheel and the brake pedaLof means governed by the absence and presence of the operator's hand on the steering wheel to press the brake pedal and set the brakes when the hands are removed from the steering wheel, said means comprising a vertically slide able bar located over the brake pedal, a latch device to hold the bar elevated, electro-magnetlc means which when energized will release said latch, a photo-electric relay, having a phototube, in circuit with said electro-magnetic means to eiIect energization of the same under predetermined light influence on the photo-tube of said relay, means to direct light rays over and adjacent said steering wheel onto said photo-tube, the arrangement being such that when the rays are in-- terrupted by hands on the steering wheel the electro-magnetic means will be inoperative, and means to efiect a rapid drop of. said bar when first released until it engages the brake pedal and thencushion the drop to give a service applica-.

tion of the brakes.

4. In motor vehicles having brake systems in which the brakes are applied by movement ot a brake pedal, and having a steering wheel, the combination with the steering wheel and the brake pedal, of means governed by the absence and presence of the operator's hand on the steering wheel to press the brake pedal and set the brakes when the hands are removed from the steering wheel, said means comprising a vertically slidable bar located over the brake pedal, a latch device to hold the bar elevated, electro-magnetic means which when energized will release said latch, a photo-electric relay, having a phototube, in circuit with said electro-magnetic means to efiectenergization of the same under predetermined light influence on the photo-tube oi said relay, means to direct light rays over and adjacent said steering wheel onto said photo-tube, the arrangement being such that when the rays are interrupted by hands on the steering wheel the electro-magnetic means will be inoperative, means to 'eifect a. rapid drop of said bar when first released until it engages the brake pedal and then cushion the drop to give a service application of the brakes, and means to adjust the cushioning action to obtain greater or lesser speeds of fall of the bar during brake application.

JOHN P. CALDWELL. 

